During semiconductor wafer fabrication, very small lithographic patterns, such as nanometer-scale lithographic patterns, can be transferred from a lithographic mask to a semiconductor wafer. In a high resolution fabrication process, for example, extreme ultraviolet (EUV) lithography, fabrication elements such as semiconductor wafers and lithographic masks may by supported on the surfaces of chucks, as they are cycled through a number of processing tools. Some of those processing tools may require a vacuum environment for performance of their precision processing steps. Through repeated use, debris comprising undesirable particles can accumulate on the surface of the chucks, causing the fabrication elements supported by them to be misaligned during a processing step, thereby resulting in fabrication involving those elements to fail.
A conventional approach to remedying the accumulation of undesirable particles on the chuck surfaces is to periodically clean those surfaces, in order to rid them of the offending debris. Typically, this is a manual process, requiring access to the interior portion of a processing tool under ambient environmental conditions. For processing tools requiring a vacuum environment for their operation, periodic cleaning involves time lost to re-establishment of vacuum conditions after cleaning is completed, in addition to the time consumed by the cleaning process itself. In many cases, the time required to restore the vacuum environment required for processing is the major factor in determining the downtime of a processing tool.
As semiconductor fabrication moves towards formation of ever finer patterns and higher resolutions, vulnerability of the entire fabrication process to irregularities in pattern transfer becomes increasingly acute, and the need for more frequent cleaning of support surfaces correspondingly great. Thus, in the context of present approaches to avoiding accumulation of undesirable particles on processing surfaces, improvements in resolution come at the cost of reduced processing efficiency.